Blueline Snapper Andaman Sea, Thailand

This spectacularly colorful school of fish contains blueline snappers, a species native to certain parts of the Indian Ocean. The fish themselves do not possess the color we see in this image. Rather, the color is in the light that shines onto them from the Sun above. The atoms and molecules in the fish—as in every object— absorb some wavelengths of light and reflect others. We do not see that particular slice of color corresponding to wavelengths of light that are absorbed. Instead, it is the wavelengths and their respective colors that reflect back to us that allow us to see the dramatic appearance of these fish.